CD274 and neoplasm: Neutrophilia may correlate with neutrophil abundance in cancers, which can contribute to a pro-tumour microenvironment by secreting VEGF, MMP-947 and reactive oxygen species.46,48 PD-L1 expression on the surface of infiltrating neutrophils may also inhibit the activation of T cells.49 Reduced levels of circulating lymphocytes may correlate with reduced T-cell lymphocyte levels in tumours, which are required for an effective T-cell response to tumour antigens, and also affect the balance between Th-1 and Th-2 phenotypes.50,51